Rough Idle, low power, and engine dies at stoplights

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bartigue
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Re: Rough Idle, low power, and engine dies at stoplights

Post by bartigue » Fri Sep 14, 2018 10:39 pm

Magnetic base and sometimes just stuck from age. It shouldn't be that hard to dislodge.
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Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
searya
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Re: Rough Idle, low power, and engine dies at stoplights

Post by searya » Sat Sep 15, 2018 11:16 am

bartigue wrote:
Fri Sep 14, 2018 10:39 pm
Magnetic base and sometimes just stuck from age. It shouldn't be that hard to dislodge.
That was it. Just pushed toward the center of the distributor and it popped off.

So the good news is the old one was absolute garbage (see pics) and with the new one in I got 754 ohms when measuring from the coil end of the wire which is in spec versus the old one which was in the 850's.

Bad news is it didn't fix it. I thought for sure that was going to do it.

I still am going to swap it again with the kit I ordered but not am guessing it won't change things.

While testing today at idle I unplugged the injectors 1 by 1.

When I unplugged cylinder 1 the car died.
When I unplugged cylinder 2 the car ran rougher
When I unplugged cylinder 3 the car ran rougher
When I unplugged cylinder 4 nothing really changed

So here is my theory. Injector #4 is getting stuck sometimes wide open (causing my catalytic converter to burn up and my pipe 4 to glow red hot) and sometimes getting stuck closed (thus no difference when I unplugged it).

Plus my sometimes I have to turn the idle way up to stay at 850 and then other times way down.

So good theory?
Sean
1984 Pininfarina Azzura
Saint Louis, Mo
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AZRuss124
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Re: Rough Idle, low power, and engine dies at stoplights

Post by AZRuss124 » Sat Sep 15, 2018 2:37 pm

One way to test is to switch the #4 injector with one of the other ones and see if the pattern moves with the injectors. It does sound like you need to have your injectors rebuilt. I would try running some injector cleaner in the fuel first
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Re: Rough Idle, low power, and engine dies at stoplights

Post by bartigue » Sun Sep 16, 2018 7:57 am

Agree on the theory and on what Russ is saying. On the bright side you have one of the most thoroughly diagnosed fuel injection systems out there.
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Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
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Re: Rough Idle, low power, and engine dies at stoplights

Post by davedecker4 » Mon Sep 17, 2018 5:07 am

If pulling #4 didn't make any difference, you might not have spark. Did you check for spark at the end of that plug wire/plug? Did you clean the contacts in the cap? Could be bad plugwire. Try pulling and swapping the wires between 3 and 4 and see if it makes a difference
Dave Decker
a 'couple' Fiats and Lancia's
searya
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Re: Rough Idle, low power, and engine dies at stoplights

Post by searya » Tue Sep 18, 2018 10:00 pm

davedecker4 wrote:
Mon Sep 17, 2018 5:07 am
If pulling #4 didn't make any difference, you might not have spark. Did you check for spark at the end of that plug wire/plug? Did you clean the contacts in the cap? Could be bad plugwire. Try pulling and swapping the wires between 3 and 4 and see if it makes a difference
Not sure if #4 Fuel Injector is it or not. Swapped another injector from my other car and not much changed :(



I am very optimistic that I will figure it out this week though. Here is what I have in store once my AR order arrives
  • New 8 mm Wires (I have tried a few of used sets already)
  • Another new set of Plugs
  • New Distributor (just got a whole new one instead of the rebuild)
  • New Control Module
  • 2 Remanufactured injectors (the ones in there are are also newly remanufactured but could still be the problem)


If that doesn't do it then I also have plans to try:
  • Wiring harness that I removed tonight from my parts car (which ran when I got it)
  • Coil from my wifes car (winter project that I plan on after this one is sorted. The engine was redone already)
  • More injectors from my wifes car
  • Using my new leak down tester to see if it shows anything

And if that doesn't do it then I am going to:
  • Cuss really loud
  • Have a drink and watch Sunday night football :lol:

With all this cool stuff I am learning I have started getting my kids in on the action. Here is a picture of my 10 year old swapping a coil pack in our family truckster.
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Sean
1984 Pininfarina Azzura
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Re: Rough Idle, low power, and engine dies at stoplights

Post by rridge » Wed Sep 19, 2018 8:28 am

Having OEM Bosch injectors cleaned and tested by a competent injector overhaul shop for spray pattern and flow rate and reinstalling them with new seals and hoses is still the best way to deal with injector problems. Aftermarket injectors and injectors adapted from other applications can cause problems. It is common to see rebuilders advertising one injector part number as applicable for five or ten different engines. The original injector part number from Bosch fit only Fiat 2L DOHC engines.

Since you have found other wiring issues in your FI wiring harness take a very good look at the injector wiring and connectors. If an injector is too worn to function properly, the plastic connector and its spring retainer are suspect as well.

When you are troubleshooting it is usually better to use known good used parts rather than new parts parts and OEM rather than aftermarket. The failure rate for unbranded ignition modules and distributor caps is high right out of the box and putting more parts of unknown performance into the system can dig your troubleshooting hole deeper.

I've often thought that the designers of engine compartments must assume that we all have a ten year old at home who can reach into places that adult hands will never touch.
Richard
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Re: Rough Idle, low power, and engine dies at stoplights

Post by bartigue » Wed Sep 19, 2018 1:41 pm

The ecu fires all four injectiors at the same time. So if you’re swapping things around and the wiring is good, etc. then I’d just start with the leakdown test. It’s harmless to perform and you’re not changing things around. If it ends up okay then move on.

Unlike Richard I’ve never had an aftermarket cap or injector fail. I’ve had cleanings not worth the cost. To each his own but if your problem is a bad injector then buy a brand new one.
-----------------------------------------------------------
Brad Artigue
1982 Spider 2000
I've restored, worked on, sold, bartered, and bled for:
1970, 1979, 1980, 1981, 1982 124 Spiders -- 1969, 1970 850 Spiders -- 77 X1/9
http://fiat.artigue.com
searya
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Re: Rough Idle, low power, and engine dies at stoplights

Post by searya » Sat Sep 22, 2018 10:45 am

bartigue wrote:
Wed Sep 19, 2018 1:41 pm
The ecu fires all four injectiors at the same time. So if you’re swapping things around and the wiring is good, etc. then I’d just start with the leakdown test. It’s harmless to perform and you’re not changing things around. If it ends up okay then move on.
So started with the leakdown test as advised.

Cylinder 1: ok in the green but not great
Cylinder 2: 90% leak out the exhaust pipe
Cylinder 3: 90% leak out the exhaust pipe

Cylinder 4: ok in the green but not great

So definitely a problem there. Before I pull the head to continue my journey I don't understand how it worked perfect the night before and then went bad the next morning? Or is there anyway that I could have the mechanical timing wrong to cause TDC to leak?

FYI I have boroscope that allows me to look into the engine so I made that both the bad cylinders were TDC by watching the piston rise/fall and the raising it back to the top again.
Sean
1984 Pininfarina Azzura
Saint Louis, Mo
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rridge
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Re: Rough Idle, low power, and engine dies at stoplights

Post by rridge » Sat Sep 22, 2018 11:14 am

Could be mis-adjusted exhaust valves, burnt exhaust valves, mis-timed exhaust cam, or head gasket leak between 2 and 3. You've already checked timing and compression. Might be time to retorque the head.
Richard
'81 Turbo Spider
Rockville, MD
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